Looper lubricating system for sewing machines



Nov. 29, 1960 R. REEBER ETAL 2,961,984

LOOPER LUBRICATING SYSTEM FOR SEWING MACHINES Filed Feb. 5, 1958 4Sheets-Sheet 1 Nov. 29, 1960 R, REEBER ErAL' 2,961,984

LOOPER LUBRICATING SYSTEM FOR SEWING MACHINES l Filed Feb. 5. 1958 4Sheets-Sheet 2 Nov. 29, 1960 R. R'l-:EBER E'r AL 2,961,984

LOOPER LUBRXCATING SYSTEM FOR SEWING MACHINES Filed Feb. 5, 1958 4Sheets-Sheet 3 Nov. 29, 1960 R. REEBER Erm. 2,961,984

LOOPER LUBRICATING SYSTEM FOR SEWING MACHINES Filed Feb. 5, 1958 4Sheets-Sheet 4 NFEN'OPS United States Patent O LOOPER LUBRICATING SYSTEMFOR SEWING MACHINES Ridolf Reeber and Paul Walter Irmscher,Kaiserslautern,

Pfalz, Germany, assignors to G. M. Pfaff A.G., Kaiserslautern, Pfalz,Germany Filed Feb. 5, 1958, Ser. No. 713,485

Claims priority, application Germany Feb. 13, 1957 6 Claims. (Cl.112M256) The invention relates to the lubrication of sewing machines andmore particularly to the lubrication of the looper race of the machines.

For this purpose a lubricant is led from a lubricant container, and itssupply to the looper race in controlled by means of a valve disposed inthe lubricant supply line.

Several requirements must be met in connection with the lubrication ofloopers, and it is dicult to establish harmony in the arrangement of thecomponents necessary to meet these requirements. It is necessary, on theone hand, especially where rapidly rotating sewing machines areconcerned, to provide the looper race with an ample supply of lubricantin order to avoid excessive heating and the results of wear. On theother hand, it is necessary to avoid that the lubricant in the looperrace comes into contact with the sewing thread. If the supply oflubricant is too strongly reduced for that purpose a black mass oflubricant remnants and of metallic wear is formed in the looper race.Although the thread absorbs only small quantities of this mass duringsewing, it is suicient to blacken the seam formation. If the lubricantsupply lis completely stopped, the so-called black sewing ceases, butthe sewing machine operates with a `dry looper race which is permissibleonly for a short period of time and below a certain number ofrevolutions.

It is, therefore, one object of the invention to provide va clean seamby maintaining the quantity of lubricant supplied to the looper racewithin such limits as are determined at the lower end by the start ofthe so-called black sewing and at the upper end by the formation ofvisible lubricant spots.

Said limits depend primarily on the type of the material being sewed.For example, when very sensitive materials are being sewed, these limitsconcide, so that not even the most careful dosing of the lubricantsupply insures obtaining a clean seam formation. It is thereforenecessary to sew sensitive materials of this kind with a -dry looperrace which, however, as previously pointed out, can only be effectedwith a slowly rotating machine.

It is, therefore, another object of the invention I'to-provide a looperlubricating system where the lubricating supply to the looper race iscontrolled in accordance with Ithe requirements established by themagnitude of the number of rotations.

In accordance with the invention this object is achieved by means of ashifting system which depends for operation on the centrifugal effectobtained after a predetermined number of rotations is attained. Saidshifting device is suitably connected to a rapidly rotating shaft of themachine, and it controls a valve which is arranged in the lubricant`supply lead to regulate the lubricant supply, i.e., it opens and closesthe valve. The lubricant supply to the looper race thus starts only whenthis number of rotations is exceeded, and it can be adjusted in such amanner that the range of numbers of rotation above that number insuressufficient lubrication, While .on the "ice other hand, it is within thelimits dictated by the cleanliness of the seam. The duration of thelubricant supply is thus always shorter than the running time of thelooper so that when many short seams are being sfewed, the looper raceis not flooded.

The centrifugal shifting device is suitably providedwith a constantshifting thrust and operates the valverby way of an intermediate member,the effective lengthof which can be adjusted in very small steps. Inthis manner it is possible to accurately dose the lamount of lubricantwhich passes through the opened valve. f

A particularly suitable system for the precise adjusting of theintermediate member, which is applicable also in valves having theshortest possible operating path and,

' therefore, small structural lengths, and the advantage of a settingmember which always remains in the same place is provided. Thus, inaccordance with a further object the invention provides that between ,a-thrust member of the centrifugal shifting device which moves in anaxial direction and Ian operating pin of the valve, `the axis" of whichis offset relative to the axis of the thrust member, the free end of alever is disposed, which is linked at the other end to a threadedspindle at a linkage point which is removed by a distance several timesthat of the oiset, which spindle is adjusted by means of `a nut andextends parallel to the shifting and the operating axes.

Further objects and details of the invention and the method of operationof the new lubricating system will become more apparent from thefollowing specification, if reference is had to the accompanyingdrawings in which Fig. l is a front elevation of acsewing machine withparts broken away to expose the lubricating system;

Fig. 2 is a longitudinal section through the essential parts Of thelubricating system; l

Fig. 3 is a section taken along the line III-III ofl-Tig. 2; `Y

Fig. 4 illustrates three steps, a, b, and c, of the course of themovements when the lubricant supply is opened, and Y .Fig 5 illustratesthe course of movements in a manner similar to Fig. 4 but with theintermediate member adjusted differently. i

The arm 1 of the sewing machine is provided with a container or tank 2(Fig. l) which is covered with a removable lid 3 to permit filling withlubricant. A lubricant supply line 4 leads from tank 2 to a valve 5 andthence to a further lubricant supply line 6 :to the looperr7. Thelubricant supply line 6 is connected to a lubricant dropping member 8which extends into a lubricant receiving portion or shell 9 ofthe looper7 whence the lubricant is conducted in a known manner to the-looperrace.

The valve 5 is secured to a molded lportion of the base plate 11 of themachine. It has a bore 12 which cornmunicates with a bore 13 of smallerdiameter. In this manner a seat 14 is formed for a valve ball 15. Thevalve ball 15 is pressed against its seat 14 rby a pressure spring 16which is supported against the nipple 17 of the-lubricant supply line 4.

A bore 18 leads radially outwardly from the bore A13 and a threadednipple 19 of the lubricant feed line 6V is connected thereto. Anoperating pin 20 for the valve 5 extends into the bore 13 and issurrounded by a gasket ring 21 which prevents the undesirable exit ofthev lubricant from the bore 13 along the operating pin ,20.v lAn insertmember 22 provided with a bore for the operating pin 20 secures thesealing gasket 21 in its position. The end of the operating pin 20projects from the insert V22 and serves for raising the valve ball 15from its seat 14 against the pressure of the spring 16 in a manner topermit a larger or smaller flow of lubricant through the valve 5.

The looper 7 is carried by the looper shaft 23 which runs in the ballbearings 24 and 25, which in turn are provided in a housing 26 secured-ina molded portion 27 of the base plate 11 of the machine by means of aset j screw 28. The end of the looper shaft 23 which is remote from thelooper 7 carries a toothed gear 29 which meshes with a gear 30 on shaft31 which in turn is mounted for rotation in a ball bearing 32 disposedin the molded portion 10.

t Two shells 33 and 34 having conical conformations are provided uponthe looper shaft 23. The shell 33 is securely fastened upon the loopershaft 23 by means of a pin while shell 34 is mounted for axial movementupon the looper. shaft 23 by means of a pin 35 which extends through alongitudinal slot 36 in the shaft. The abutment of the pin 35 at the endof longitudinal slot 36 limits the axial movement.

I An axial bore 37 is provided in the looper shaft 23 at the end remotefrom the looper 7 into which a shifting or thrust rod 38 is mountedwhich has a piston shaped end 39 abutting against the pin 35. At itsother end thrust rod 38 is mounted in a bore of the counter bearing 40for a spring 41 and extends beyond the end of the looper shaft 23. 'I'hespring 41 is disposed between counter bearing 40 and the piston shapedend 39 of the thrust rod 38 and presses the shells 33 and 34 againsteach other by way of pin 35. The counter bearing 40 is in threadedengagement with the end portion of bore 37. In this manner it ispossible to adjust the pressure of the spring 41 and thus the force withwhich the shells 33 and 34 are pressed against each other.

Shells 33 and 34 enclose halls 42 which as a result of the centrifugalforce developed by the rotation of the looper shaft 23 have a tendencyto force shells 33 and 34 apart. The force of spring 41 however opposesthis separation as long as this force is greater than that exerted byballs 42. If the centrifugal force overcomes that of the spring theradial distance of balls 42 from the axis of rotation increases andconsequently also the centrifugal force whereupon the shells 33 and 34move apart suddenly until the pin 35 abuts the end of the longitudinalslot 36. When the number of rotations decreases the opposite processtakes place, i.e. the shells 33 and 34 suddenly move together.

It is possible for the shell 34 to move only relative to the loopershaft 23 in which connection the movement is transferred to the pin 35and to the thrust rod member 38. Thus the thrust rod executes a thrustof constant length corresponding to the length of the longitudinal slot36 when the number of rotations corresponding to the pressure of spring41 is exceeded or decreased.

j Thrust member 38 and operating pin 20 are oset laterally with respectto one another as indicated in Figs.

3 to 5. Between the two the free end 43 of lever 44 is disposed which islinked by means of a bolt 45 to a threaded spindle 46 and which isguided in a bifurcated member 47 secured to molded portion 10. Thethreaded spindle 46 is journalled for longitudinal sliding in a sleeve48 which in turn is secured to molded portion 27 of the base plate 11 ofthe machine by means of a set screw 49. .A pressure spring 51 engages anabutment 50 of the spindle 46 and rests with its other end against thesleeve 48. The pressure spring 51 upon the threaded spindle 46 istightened against the sleeve by means of a knurled nut 52. Rotating thenut 52 permits shifting of the spindle 46 and thus of bolt 45 whichserves as the linkage point for lever 44 in a manner that pressurespring 51 permits not only adjustment without tolerance but alsoprovides a frictional force which secures the adjusting nut 52 againstunintentional setting.

The free end 43 of lever 44 is provided at its area of contact with theoperating pin 20 with an abutment plane 53 (Fig. 4) which is convexlycurved. At the contact area with the thrust member 38 a pressure member55 is 4 provided which is movable about a pivot bolt 54 and presents aplane abutment surface 56.

In the position of rest the thrust rod 38 is in the phase a indicated inFigs. 4 and5.

As the shifting thrust is executed rod 38 first moves into engagementwith the pressure member 55 so that this member adjusts itself with itsabutment plane 56 perpendicular to the `axis of the thrust rod (phaseb). Continuing movement of the thrust rod 38 causes pressure member 55to move the free end 43 of lever 44 and carry along the operating pin 20and in this connection the extent of the valve opening thrust dependsupon the position of the linkage point of lever 44. The position of thatpoint determines the angular location of lever 44 and thus the effectivelength between engagement planes 53 and 56 of the intermediate memberwhich is constituted of the parts 43 and 55. rIhe effective length ofthe intermediate member 43, 55 is greater in Fig. 4 as in Fig. 5. Ihepath of the operating pin 20 is also greater by the same amount becausethe thrust member 38 in both instances effects the same amount ofthrust. The effective length of the intermediatae member 43, 55 can alsobe readlly and accurately changed with the thrust member 38 in operativeposition by turning the adjusting nut 52.

Having now described our invention with reference to the embodimentillustrated herein, we do not wish to be limited thereto, but what wedesire to protect by Letters Patent is set forth in the appended claims.

We claim:

1. In a sewing machine of the type having a looper drive shaft and alooper supported endwise of said drive shaft and having a lubricantreceiving portion, a lubricating system for the looper race comprising alubricant container, a feed line extending from said container to saidreceiving portion, and automatically operative feed control meansprovided in operative relationship to said feed line and having a feedcontrol portion including a valve or the like associated with said feedline and a centrifugally actuated shifting portion mounted on saidlooper shaft and having a portion movable axially of said shaft andoperatively connected to said valve, said shifting portion comprising acentrifugal device associated with said shaft and responsive to thecentrifugal force imparted thereto by said shaft.

2. In a sewing machine of the type having a looper drive shaft and alooper supported endwise of said drive shaft and having a lubricantreceiving portion, a lubricating system for the looper race comprising alubricant container, a feed line extending from said container to saidreceiving portion, and automatically operative feed control meansprovided in operative relationship to said feed line and having a feedcontrol portion including a valve or the like associated with said feedline and a cen trifugally actuated shifting portion mounted on saidlooper shaft and having a portion movable axially of said v shaft andoperatively connected to said valve, said shifting portion comprising acentrifugal device associated with said shaft and responsive to thecentrifugal force imparted thereto by said shaft, and a force transfermeans having a portion of adjustable effective length disposedintermediate said shifting portion and said valve and said shiftingportion including a thrust member havling one end in operativeengagement with said transfer means and being movable over a path ofpredetermined length.

3. In a sewing machine of the type having a looper drive shaft and alooper supported endwise of said drive shaft and having a lubricantreceiving portion, a lubricating system for the looper race comprising alubricant container, `a feed line extending from said container to saidreceiving portion, and automatically operative feed control meansprovided in operative relationship to said feed line and having a feedcontrol portion including a valve or the like associated with said feedline and a centrifugally actuated shifting portion mounted on saidlooper shaft and having a portion movable axially of said shaft andoperatively connected to said valve, said shifting portion comprising acentrifugal device associated with said shaft and responsive to thecentrifugal force imparted thereto by' said shaft, `and a force transfermeans having a portion of adjustable effective length disposedintermediate said shifting portion and said valve, said shifting portionincluding a thrust member having one end in operative engagement withsaid transfer means and being movable over a path of predeterminedlength, said thrust member being movable axially of said shaft and saidcontrol portion including a valve having an operating pin extendingparallel to and offset relative to the axis of said thrust member, andsaid force transfer means including an adjustable threaded spindlemounted on the base of the machine, and extending parallel to the axesof said thrust member and said operating pin at a distance several timesthe magnitude of the offset distance and a lever defining said portionof adjustable effective length at its free end intermediate said thrustmember and said operating pin and having its other end linked to saidadjustable threaded spindle.

4. In a sewing machine of the type having a looper drive shaft and alooper supported endwise of said drive shaft and having a lubricantreceiving portion, a lubricating system for the looper race comprising alubricant container, a feed line extending from said container to saidreceiving portion, and feed control means provided in operativerelationship to said feed line and having a feed control portionassociated with said feed line and a centrifugally actuated shiftingportion operatively connected to said feed control portion, saidshifting portion comprising a centrifugal device associated with saidshaft and responsive to the centrifugal force imparted thereto by saidshaft, and a force transfer means having a portion of adjustableeffective length disposed intermediate said shifting portion and saidfeed control portion, said shifting portion including a thrust memberhaving one end in operative engagement with said transfer means andbeing movable over a path of predetermined length, said thrust memberbeing movable axially of said shaft and said control portion including avalve having an operating pin extending parallel to and offset relativeto the axis of said thrust member, and said force transfer meansincluding an adjustable threaded spindle mounted on the base of themachine, and extending parallel to the axes of said thrust member andsaid operating pin at a distance several times the magnitude of theoffset distance and a lever defining said portion of adjustableeffective length at its free end intermediate said thrust member landsaid operating pin and having its other end linked .to said adjustablethreaded spindle, said lever presenting a convex contact surfaceproximate said operating pin and a pivotally mounted pressure memberhaving an engagement surface disposed endwise of said thrust member, andsaid thrust member being rotatable with said shaft.

5. In a sewing machine of fthe type having a looper drive shaft and alooper supported endwise of said drive shaft and having a lubricantreceiving portion, a lubricating system for the looper race comprising alubricant container, a feed line extending from said container to saidreceiving portion, and feed control means provided in operativerelationship to said feed line and having a feed control portionassociated with said feed line and a centrifugally actuated shiftingportion operatively connected to said feed control portion, saidshifting portion comprising a centrifugal device associated with saidshaft and responsive to the centrifugal force imparted thereto by saidshaft, and a force transfer means having a portion of adjustableeffective length disposed intermediate said shifting portion and saidfeed control portion, said shifting portion including a thrust memberhaving one end in operattive engagement with said transfer means andbeing movable over a path of predetermined length, said thrust memberbeing movable axially of said shaft and said control portion including avalve having an operating pin extending parallel to and offset relativeto the axis of said thrust member, and said force transfer meansincluding an adjustable threaded spindle mounted on the base of themachine, and extending parallel to the axes of said thrust member andsaid operating pin at a distance several times the magnitude of theoffset distance and a lever defining said portion of adjustableeffective length at its free end intermediate said thrust member andsaid operating pin and having its other end linked lto said adjustablethreaded spindle, said threaded spindle presenting a first abutment andbeing mounted on the base of the machine and a spring biasing saidthreaded spindle having one end in engagement with said first abutmentand the other end in engagement with a second abutment defined on saidmachine base.

6. In a sewing machine of the type having a looper drive shaft and alooper supported endwise of said drive shaft and having a lubricantreceiving portion, a lubricating system for the looper race comprising alubricant container, a feed line extending from said container to saidreceiving portion, and feed control means provided in operativerelationship to said feed line and having a feed control portionassociated with said feed line and a centrifugally actuated shiftingportion mounted on said looper shaft and having a portion movableaxially of said shaft and operatively connected to said feed controlportion, said shifting portion comprising a centrifugal deviceassociated with said shaft and responsive to the centrifugal forceimparted thereto by said shaft, and a force transfer means having -aportion of adjustable effective length disposed intermediate saidshifting portion and said feed control portion, said shifting portionincluding a thrust member having one end in operative engagement withsaid transfer means and being movable over a path of predeterminedlength, said thrust member being movable -axially of said shaft and saidcontrol portion including a valve having an operating pin extendingparallel to and offset relative to 'the axis of said thrust member, andsaid force transfer means including an adjustable threaded spindlemounted on the base of the machine, and extending parallel to :the axesof said thrust member and said operating pin at a distance several timesthe magnitude of `the offset distance and a lever defining said portionof adjustable effective length at its free end intermediate said thrustmember and said operating pin and having its other end linked to saidadjustable threaded spindle, said centrifugal device including a portionfixedly secured to said looper drive shaft and a slidable portionmovable axially of said shaft in response to centrifugal force and saidthrust member being mounted in a hollow portion of said shaft with itsother end in operative engagement with said slidable portion and aspring biasing said thrust member in the direction of said slidableportion, and an adjustabie means mounted on said shaft proximate saidone end of said thrust member operative to set the spring for apredetermined bias correspond-ing to `a number of revolutions of saidcentrifugal device above which said thrust member becomes operative.

References Cited in the file of this patent UNITED STATES PATENTS1,936,372 Waterman Nov. 2l, 1933 1,962,090 Gjerde June 5, 1934 1,968,023IBijur July 31, 1934 2,283,869 Graesser May 19, 1942 2,453,827 AlberoNov. 16, 1948 2,535,703 Smith et al Dec. 26, 1950

